1. Technical Field
The presently disclosed subject matter relates to semiconductor light emitting apparatuses, and in particular, to a semiconductor light emitting apparatus that uses a semiconductor light emitting device and a wavelength converting material such as a phosphor in combination.
2. Description of the Related Art
Semiconductor light emitting apparatuses have been conventionally known that use a semiconductor light emitting device and a wavelength converting material such as a phosphor in combination in order to emit light in which color (tone) is changed from the original color (tone) originating from the semiconductor light emitting device to a second different color (tone). One example of such a semiconductor light emitting apparatus is shown in FIG. 1.
This type of semiconductor light emitting apparatus can include a resin housing 52 with which a pair of leads 50 and 51 are integrated. Inside the resin housing 52 a first recessed portion 54 is formed. Above the first recessed portion 54 a second recessed portion 53 with a larger diameter than that of the first recessed portion 54 is continuously formed.
A semiconductor light emitting device 55 can be mounted on and/or adjacent to the bottom of the first recessed portion 54. Not-shown electrodes of the semiconductor light emitting device 55 are electrically connected to the respective leads 50 and 51 by means of bonding wires 56 and 57.
A transparent resin material is mixed with a particular wavelength converting material such as a particular phosphor to prepare a phosphor-containing resin 58, which is charged into the first recessed portion 54 to resin-seal the semiconductor light emitting device 55. On the phosphor-containing resin 58 and inside the second recessed portion 53 another transparent resin material 59 is charged, thereby completing the semiconductor light emitting apparatus (see, for example, Japanese Patent Application Laid-Open No. 2002-33520).
The semiconductor light emitting apparatus configured as described above is referred to as a surface mount type and is used as a light source for use in a portable handy terminal or the like.
This type of semiconductor light emitting apparatus can be configured in such a manner that a soft resin material is used as the transparent resin material for constituting the phosphor-containing resin 58 which is charged into the first recessed portion 54 to resin-seal the semiconductor light emitting device 55, and a hard resin material is used as the transparent resin material 59 which is charged into the second recessed portion 53 on the phosphor-containing resin 58. However, the following problems may arise in this configuration.
When the environmental test (heat cycle test) is performed on the semiconductor light emitting apparatus configured as described above, the phosphor-containing resin 58 can repeatedly expand and contract in accordance with the temperature change during the heat cycle. When the phosphor-containing resin 58 expands, an external force may be applied to the transparent resin material 59 which forms the boundary between the phosphor-containing resin 58. As a result, the transparent resin material 59 may become detached and can be peeled from the contact area with the stepped area 60 where the boundary between the phosphor-containing resin 58 and the transparent resin material 59 (between the first and second recessed portions 54 and 53) is formed, thereby easily forming a crack 61 at that area and adjacent areas.
This phenomenon may occur even during the normal operation conditions. For example, it may occur due to the repeated turning-on and turning-off of the semiconductor light emitting device which leads to repeated generation of heat and cooling of the semiconductor light emitting device.